Two Gibberellin Biosynthetic Pathways Operated in Spinach Beet Leaves

The metabolism of [¹⁴C]GA₁₂ in spinach beet (Beta vulgaris L. subsp. cicla) leaves was examined to determine the pathway of endogenous gibberellins in seedling stage. [¹⁴C]GA₁₂ was metabolized to GA?₃, GA₄₄, GA₁?, GA₂?, GA₁, GA8, GA₁?, GA₂₄, GA?, GA₃?, and GA₄. Radioactivity of GAs in the early C-13 hydroxylation route was three times higher than that in the non C-13 hydroxylation route in analyzed GA-metabolites. Radioactivity of GA₁ was always higher than that of GA₄ at every feeding time. The major pathway of endogenous GA metabolism in spinach beet leaves might be the early C-13 hydroxylation pathway.